Inverse discrete cosine transform (IDCT) is widely applied in decoding of video data. When a terminal user views a video program, a decoder in a display apparatus will decode encoded data of the video program by adopting the inverse discrete cosine transform algorithm, so that the video program is able to be displayed on a display panel.
In existing video decoding process, a relatively complicated decoding algorithm can be set to obtain an image having a clear picture and a high quality of display effect. However, the relatively complicated decoding algorithm would reduce efficiency of decoding process, so as to affect response speed of picture display in the process of viewing. In addition, when the decoding algorithm is simplified to improve decoding performance, accuracy of decoding process and precision of decoding output data will be decreased. For example, data loss will occur in decoding output data, thereby causing that the difference between display areas having different gray scale values increases. Accordingly, softness of the display picture decreases and a disadvantageous influence will be made on viewing.